U.S. patent number 6,971,969 [Application Number 10/799,566] was granted by the patent office on 2005-12-06 for method and device for determining transmission state of power transmission device for internal combustion engine driven vehicle.
This patent grant is currently assigned to Kokusan Denki Co., Ltd.. Invention is credited to Kazuyoshi Kishibata, Yuichi Kitagawa, Hiroyasu Sato.
United States Patent |
6,971,969 |
Kitagawa , et al. |
December 6, 2005 |
Method and device for determining transmission state of power
transmission device for internal combustion engine driven
vehicle
Abstract
A transmission state determination method of a power
transmission device for an internal combustion engine driven
vehicle including steps of: driving a generator by an internal
combustion engine with a vehicle driven by the internal combustion
engine stopped; performing an intake air amount gradually
increasing process for gradually increasing the intake air amount
of the internal combustion engine when the internal combustion
engine is controlled so as to generate predetermined power from the
generator; determining that the power transmission device for
transmitting the output of the internal combustion engine to wheels
of the vehicle is in a state of transmitting power when slight
movement of a vehicle body is detected in the intake air amount
gradually increasing process; and determining that the power
transmission device is in a state of cutting power transmission
when movement of the vehicle body is not detected in the intake air
amount gradually increasing process.
Inventors: |
Kitagawa; Yuichi (Numazu,
JP), Kishibata; Kazuyoshi (Numazu, JP),
Sato; Hiroyasu (Numazu, JP) |
Assignee: |
Kokusan Denki Co., Ltd.
(Shizuoka-ken, JP)
|
Family
ID: |
32959337 |
Appl.
No.: |
10/799,566 |
Filed: |
March 11, 2004 |
Foreign Application Priority Data
|
|
|
|
|
Mar 13, 2003 [JP] |
|
|
2003-068655 |
|
Current U.S.
Class: |
477/3;
180/65.265; 180/65.27 |
Current CPC
Class: |
B60W
40/12 (20130101); B60W 30/18054 (20130101); B60W
10/02 (20130101); B60K 28/10 (20130101); B60W
10/04 (20130101); F02D 11/105 (20130101); B60W
2520/10 (20130101); Y10T 477/679 (20150115); F02D
41/0002 (20130101); B60W 2510/0638 (20130101); Y10T
477/23 (20150115); B60W 2710/0644 (20130101); B60W
2710/0605 (20130101) |
Current International
Class: |
B60K 001/02 () |
Field of
Search: |
;477/3
;180/65.4,65.2 |
References Cited
[Referenced By]
U.S. Patent Documents
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|
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6138069 |
October 2000 |
Ellertson et al. |
6494277 |
December 2002 |
Boggs et al. |
|
Foreign Patent Documents
Primary Examiner: Wright; Dirk
Attorney, Agent or Firm: Pearne & Gordon LLP
Claims
What is claimed is:
1. A transmission state determination method of a power
transmission device for an internal combustion engine driven
vehicle for determining whether said power transmission device is
in a state of cutting power transmission or a state of transmitting
power, said vehicle comprising: an internal combustion engine
incorporated in a vehicle body having drive wheels; an AC generator
incorporated in said vehicle body and driven by said internal
combustion engine; mode selection means for selecting a control
mode of said internal combustion engine between a control mode for
driving vehicle and a control mode for generating electric power;
and a generation control unit having rotational speed control means
for generating electric power for controlling an intake air amount
of said internal combustion engine so as to rotate said internal
combustion engine at a rotational speed required for generating
predetermined power from said generator when the control mode for
generating electric power is selected by said mode selection means,
wherein said power transmission device has a transmission with a
gear position for cutting power transmission and an automatic
clutch mechanism and is provided between a crankshaft of said
internal combustion engine and said drive wheels, and a
displacement sensor that can detect movement of said vehicle body
is provided, said method comprises steps of; gradually increasing
the intake air amount of said internal combustion engine while a
rotational speed of said internal combustion engine is monitored
when said control mode for generating electric power is selected,
and determining that said power transmission device is in the state
of transmitting power when said displacement sensor detects
movement of said vehicle body in the step of gradually increasing
said intake air amount, and that said power transmission device is
in the state of cutting power transmission when said displacement
sensor does not detect movement of said vehicle body before the
rotational speed of said internal combustion engine exceeds a
preset reference rotational speed in the step of gradually
increasing said intake air amount.
2. A transmission state determination method of a power
transmission device for an internal combustion engine driven
vehicle for determining whether said power transmission device is
in a state of cutting power transmission or a state of transmitting
power, said vehicle comprising: an internal combustion engine
incorporated in a vehicle body having drive wheels; an AC generator
incorporated in said vehicle body and driven by said internal
combustion engine; mode selection means for selecting a control
mode of said internal combustion engine between a control mode for
driving vehicle and a control mode for generating electric power;
and a generation control unit having rotational speed control means
for generating electric power for controlling an intake air amount
of said internal combustion engine so as to rotate said internal
combustion engine at a rotational speed required for generating
predetermined power from said generator when the control mode for
generating electric power is selected by said mode selection means,
wherein said power transmission device has a transmission with a
gear position for cutting power transmission and an automatic
clutch mechanism and is provided between a crankshaft of said
internal combustion engine and said drive wheels, and a vehicle
speed sensor that generates a vehicle speed pulse for each rotation
of an axle of said vehicle through a certain angle is used as a
displacement sensor, and said method comprises steps of; gradually
increasing an intake air amount of said internal combustion engine
while a rotational speed of said internal combustion engine is
monitored when said control mode for generating electric power is
selected, and determining that said power transmission device is in
the state of transmitting power when generation of the vehicle
speed pulse by said vehicle speed sensor is detected in the process
of gradually increasing said intake air amount, and that said power
transmission device is in the state of cutting power transmission
when generation of the vehicle speed pulse by the vehicle speed
sensor is not detected before the rotational speed of said internal
combustion engine exceeds a preset reference rotational speed in
the process of gradually increasing said intake air amount.
3. A transmission state determination method of a power
transmission device for an internal combustion engine driven
vehicle for determining whether said power transmission device is
in a state of cutting power transmission or a state of transmitting
power, said vehicle comprising: an internal combustion engine
incorporated in a vehicle body having drive wheels; an AC generator
incorporated in said vehicle body and driven by said internal
combustion engine; mode selection means for selecting a control
mode of said internal combustion engine between a control mode for
driving vehicle and a control mode for generating electric power;
and a generation control unit having rotational speed control means
for generating electric power for controlling an intake air amount
of said internal combustion engine so as to rotate said internal
combustion engine at a rotational speed required for generating
predetermined power from said generator when the control mode for
generating electric power is selected by said mode selection means,
wherein said power transmission device has a transmission with a
gear position for cutting power transmission and an automatic
clutch mechanism and is provided between a crankshaft of said
internal combustion engine and said drive wheels, and a vehicle
speed sensor that generates a vehicle speed pulse for each rotation
of an axle of said vehicle through a certain angle is used as a
displacement sensor, and said method comprises steps of; gradually
increasing a intake air amount of said internal combustion engine
while a rotational speed of said internal combustion engine is
monitored when said control mode for generating electric power is
selected, and determining that said power transmission device is in
the state of transmitting power when a vehicle speed obtained from
said vehicle speed pulse reaches a set determination reference
value or higher in the process of gradually increasing said intake
air amount, and that said power transmission device is in the state
of cutting power transmission when the vehicle speed obtained from
said vehicle speed pulse does not reach said set determination
reference value before the rotational speed of said internal
combustion engine exceeds a preset reference rotational speed in
the process of gradually increasing said intake air amount.
4. A transmission state determination device of a power
transmission device for an internal combustion engine driven
vehicle for determining whether said power transmission device is
in a state of cutting power transmission or a state of transmitting
power, said vehicle comprising: an internal combustion engine
incorporated in a vehicle body having drive wheels; an AC generator
incorporated in said vehicle body and driven by said internal
combustion engine; mode selection means for selecting a control
mode of said internal combustion engine between a control mode for
driving vehicle and a control mode for generating electric power;
and a generation control unit having rotational speed control means
for generating electric power for controlling an intake air amount
of said internal combustion engine so as to rotate said internal
combustion engine at a rotational speed required for generating
predetermined power from said generator when the control mode for
generating electric power is selected by said mode selection means,
wherein said power transmission device has a transmission with a
gear position for cutting power transmission and an automatic
clutch mechanism and is provided between a crankshaft of said
internal combustion engine and said drive wheels, and said
transmission state determination device comprises: rotational speed
detection means for detecting a rotational speed of said internal
combustion engine; a displacement sensor that detects movement of
said vehicle body; intake air amount control means for determining
transmission state for controlling said actuator so as to gradually
increase the intake air amount of said internal combustion engine
when the control mode for generating electric power is selected by
said mode selection means; and determination means for determining
that said power transmission device is in the state of transmitting
power when said displacement sensor detects movement of said
vehicle body in the process of gradually increasing said intake air
amount by said intake air amount control means for determining
transmission state, and that said power transmission device is in
the state of cutting power transmission when said displacement
sensor does not detect movement of said vehicle body before the
rotational speed detected by said rotational speed detection means
exceeds a set reference rotational speed in the process of
gradually increasing said intake air amount.
5. A transmission state determination device of a power
transmission device for an internal combustion engine driven
vehicle for determining whether said power transmission device is
in a state of cutting power transmission or a state of transmitting
power, said vehicle comprising: an internal combustion engine
incorporated in a vehicle body having drive wheels; an AC generator
incorporated in said vehicle body and driven by said internal
combustion engine; mode selection means for selecting a control
mode of said internal combustion engine between a control mode for
driving vehicle and a control mode for generating electric power;
and a generation control unit having rotational speed control means
for generating electric power for controlling an intake air amount
of said internal combustion engine so as to rotate said internal
combustion engine at a rotational speed required for generating
predetermined power from said generator when the control mode for
generating electric power is selected by said mode selection means,
wherein said power transmission device has a transmission with a
gear position for cutting power transmission and an automatic
clutch mechanism and is provided between a crankshaft of said
internal combustion engine and said drive wheels, and said
transmission state determination device comprises: rotational speed
detection means for detecting a rotational speed of said internal
combustion engine; a vehicle speed sensor that generates a vehicle
speed pulse for each rotation of an axle of said vehicle through a
certain angle; intake air amount control means for determining
transmission state for controlling said actuator so as to gradually
increase the intake air amount of said internal combustion engine
when the control mode for generating electric power is selected by
said mode selection means; and determination means for determining
that said power transmission device is in the state of transmitting
power when said vehicle speed pulse is detected in the process of
gradually increasing said intake air amount by said intake air
amount control means for determining transmission state, and that
said power transmission device is in the state of cutting power
transmission when said vehicle speed pulse is not detected before
the rotational speed detected by said rotational speed detection
means exceeds a reference rotational speed in the process of
gradually increasing said intake air amount.
6. A transmission state determination device of a power
transmission device for an internal combustion engine driven
vehicle for determining whether said power transmission device is
in a state of cutting power transmission or a state of transmitting
power, said vehicle comprising: an internal combustion engine
incorporated in a vehicle body having drive wheels; an AC generator
incorporated in said vehicle body and driven by said internal
combustion engine; mode selection means for selecting a control
mode of said internal combustion engine between a control mode for
driving vehicle and a control mode for generating electric power;
and a generation control unit having rotational speed control means
for generating electric power for controlling an intake air amount
of said internal combustion engine so as to rotate said internal
combustion engine at a rotational speed required for generating
predetermined power from said generator when the control mode for
generating electric power is selected by said mode selection means,
wherein said power transmission device has a transmission with a
gear position for cutting power transmission and an automatic
clutch mechanism and is provided between a crankshaft of said
internal combustion engine and said drive wheels, and said
transmission state determination device comprises: rotational speed
detection means for detecting a rotational speed of said internal
combustion engine; a vehicle speed sensor that generates a vehicle
speed pulse for each rotation of an axle of said vehicle through a
certain angle; intake air amount control means for determining
transmission state for controlling said actuator so as to gradually
increase the intake air amount of said internal combustion engine
when the control mode for generating electric power is selected by
said mode selection means; and determination means for determining
that said power transmission device is in the state of transmitting
power when a vehicle speed obtained from said vehicle speed pulse
reaches a set determination reference value or higher in the
process of gradually increasing said intake air amount by said
intake air amount control means for determining transmission state,
and that said power transmission device is in the state of cutting
power transmission when the vehicle speed obtained from said
vehicle speed pulse does not reach said determination reference
value before the rotational speed of said internal combustion
engine exceeds a predetermined reference rotational speed in the
process of gradually increasing said intake air amount.
7. A runaway prevention device of an internal combustion engine
driven vehicle for preventing runaway of said internal combustion
engine driven vehicle when a control mode for generating electric
power is selected, said internal combustion engine driven vehicle
comprising: an internal combustion engine incorporated in a vehicle
body having drive wheels; a power transmission device that has a
transmission with a gear position for cutting power transmission
and an automatic clutch mechanism that enters a state of
transmitting power when a rotational speed of the internal
combustion engine reaches a predetermined power transmission start
rotational speed or higher, and is provided between a crankshaft of
said internal combustion engine and said drive wheels; an actuator
that operates means for adjusting an intake air amount of said
internal combustion engine; an AC generator incorporated in said
vehicle body and driven by said internal combustion engine; mode
selection means for selecting a control mode of said internal
combustion engine between a control mode for driving vehicle and a
control mode for generating electric power; and a generation
control unit having rotational speed control means for generating
electric power for controlling the intake air amount of said
internal combustion engine so as to rotate said internal combustion
engine at a rotational speed required for generating predetermined
power from said generator when the control mode for generating
electric power is selected by said mode selection means, wherein
said runaway prevention device comprises: rotational speed
detection means for detecting a rotational speed of said internal
combustion engine; a displacement sensor that detects movement of
said vehicle body; intake air amount control means for determining
transmission state for controlling said actuator so as to gradually
increase the intake air amount of said internal combustion engine
when the control mode for generating electric power is selected by
said mode selection means; determination means for determining that
said power transmission device is in a state of transmitting power
when said displacement sensor detects movement of said vehicle body
in the process of gradually increasing said intake air amount by
said intake air amount control means for determining transmission
state, and that said power transmission device is in a state of
cutting power transmission when said displacement sensor does not
detect movement of said vehicle body before the rotational speed
detected by said rotational speed detection means exceeds a set
reference rotational speed in the process of gradually increasing
said intake air amount; and safety means for controlling said
internal combustion engine so as to return the rotational speed of
said internal combustion engine to a rotational speed less than
said power transmission start rotational speed or to stop said
internal combustion engine when said determination means determines
that said power transmission device is in the state of transmitting
power.
8. The runaway prevention device of the internal combustion engine
driven vehicle according to claim 7, wherein said safety means is
comprised of means for controlling said actuator so as to return
said intake air amount to an idle air amount when said
determination means determines that said power transmission device
is in the state of transmitting power.
9. The runaway prevention device of the internal combustion engine
driven vehicle according to claim 7, wherein said safety means is
comprised of means for stopping an ignition operation of said
internal combustion engine when said determination means determines
that said power transmission device is in the state of transmitting
power.
10. The runaway prevention device of the internal combustion engine
driven vehicle according to claim 7, wherein said safety means is
comprised of means for stopping supply of fuel to said internal
combustion engine when said determination means determines that
said power transmission device is in the state of transmitting
power.
11. A runaway prevention device of an internal combustion engine
driven vehicle for preventing runaway of said internal combustion
engine driven vehicle when a control mode for generating electric
power is selected, said internal combustion engine driven vehicle
comprising: an internal combustion engine incorporated in a vehicle
body having drive wheels; a power transmission device that has a
transmission with a gear position for cutting power transmission
and an automatic clutch mechanism that enters a state of
transmitting power when a rotational speed of the internal
combustion engine reaches a predetermined power transmission start
rotational speed or higher, and is provided between a crankshaft of
said internal combustion engine and said drive wheels; an actuator
that operates means for adjusting an intake air amount of said
internal combustion engine; an AC generator incorporated in said
vehicle body and driven by said internal combustion engine; mode
selection means for selecting a control mode of said internal
combustion engine between a control mode for driving vehicle and a
control mode for generating electric power; and a generation
control unit having rotational speed control means for generating
electric power for controlling the intake air amount of said
internal combustion engine so as to rotate said internal combustion
engine at a rotational speed required for generating predetermined
power from said generator when the control mode for generating
electric power is selected by said mode selection means, wherein
said runaway prevention device comprises: rotational speed
detection means for detecting a rotational speed of said internal
combustion engine; a vehicle speed sensor that generates a
plurality of vehicle speed pulses for one rotation of an axle of
said vehicle; intake air amount control means for determining
transmission state for controlling said actuator so as to gradually
increase the intake air amount of said internal combustion engine
when the control mode for generating electric power is selected by
said mode selection means; determination means for determining that
said power transmission device is in a state of transmitting power
when said vehicle speed pulses are detected in the process of
gradually increasing said intake air amount by said intake air
amount control means for determining transmission state, and that
said power transmission device is in a state of cutting power
transmission when said vehicle speed pulses are not detected before
the rotational speed detected by said rotational speed detection
means exceeds a set reference rotational speed in the process of
gradually increasing said intake air amount; and safety means for
controlling said internal combustion engine so as to return the
rotational speed of said internal combustion engine to a rotational
speed less than said power transmission start rotational speed or
to stop said internal combustion engine when said determination
means determines that said power transmission device is in the
state of transmitting power.
12. The runaway prevention device of the internal combustion engine
driven vehicle according to claim 11, wherein said safety means is
comprised of means for controlling said actuator so as to return
said intake air amount to an idle air amount when said
determination means determines that said power transmission device
is in the state of transmitting power.
13. The runaway prevention device of the internal combustion engine
driven vehicle according to claim 11, wherein said safety means is
comprised of means for stopping an ignition operation of said
internal combustion engine when said determination means determines
that said power transmission device is in the state of transmitting
power.
14. The runaway prevention device of the internal combustion engine
driven vehicle according to claim 11, wherein said safety means is
comprised of means for stopping supply of fuel to said internal
combustion engine when said determination means determines that
said power transmission device is in the state of transmitting
power.
15. A runaway prevention device of an internal combustion engine
driven vehicle for preventing runaway of said internal combustion
engine driven vehicle when a control mode for generating electric
power is selected, said internal combustion engine driven vehicle
comprising: an internal combustion engine incorporated in a vehicle
body having drive wheels; a power transmission device that has a
transmission with a gear position for cutting power transmission
and an automatic clutch mechanism that enters a state of
transmitting power when a rotational speed of the internal
combustion engine reaches a predetermined power transmission start
rotational speed or higher, and is provided between a crankshaft of
said internal combustion engine and said drive wheels; an actuator
that operates means for adjusting an intake air amount of said
internal combustion engine; an AC generator incorporated in said
vehicle body and driven by said internal combustion engine; mode
selection means for selecting a control mode of said internal
combustion engine between a control mode for driving vehicle and a
control mode for generating electric power; and a generation
control unit having rotational speed control means for generating
electric power for controlling the intake air amount of said
internal combustion engine so as to rotate said internal combustion
engine at a rotational speed required for generating predetermined
power from said generator when the control mode for generating
electric power is selected by said mode selection means, wherein
said runaway prevention device comprises: rotational speed
detection means for detecting a rotational speed of said internal
combustion engine; a vehicle speed sensor that generates a
plurality of vehicle speed pulses for one rotation of an axle of
said vehicle; intake air amount control means for determining
transmission state for controlling said actuator so as to gradually
increase the intake air amount of said internal combustion engine
when the control mode for generating electric power is selected by
said mode selection means; determination means for determining that
said power transmission device is in a state of transmitting power
when a vehicle speed obtained from said vehicle speed pulses
reaches a set determination reference value or higher in the
process of gradually increasing said intake air amount by said
intake air amount control means for determining transmission state,
and that said power transmission device is in a state of cutting
power transmission when the vehicle speed obtained from the vehicle
speed pulses does not reach said determination reference value
before the rotational speed of said internal combustion engine
exceeds a predetermined reference rotational speed; and safety
means for controlling said internal combustion engine so as to
return the rotational speed of said internal combustion engine to a
rotational speed less than said power transmission start rotational
speed or to stop said internal combustion engine when said
determination means determines that said power transmission device
is in the state of transmitting power.
16. The runaway prevention device of an internal combustion engine
driven vehicle according to claim 15, wherein said safety means is
comprised of means for controlling said actuator so as to return
said intake air amount to an idle air amount when said
determination means determines that said power transmission device
is in the state of transmitting power.
17. The runaway prevention device of an internal combustion engine
driven vehicle according to claim 15, wherein said safety means is
comprised of means for stopping an ignition operation of said
internal combustion engine when said determination means determines
that said power transmission device is in the state of transmitting
power.
18. The runaway prevention device of an internal combustion engine
driven vehicle according to claim 15, wherein said safety means is
comprised of means for stopping supply of fuel to said internal
combustion engine when said determination means determines that
said power transmission device is in the state of transmitting
power.
Description
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a transmission state determination
method, in an internal combustion engine driven vehicle
incorporating a power supply unit that drives a generator by an
internal combustion engine to supply power to a load when the
vehicle is stopped, for determining whether a power transmission
device for transmitting rotation of the internal combustion engine
to drive wheels of the vehicle is in a state of cutting power
transmission at the time of generation, a transmission state
determination device used for implementing the method, and a
runaway prevention device of the internal combustion engine driven
vehicle for preventing runaway of the vehicle at the time of
generation by using the determination device.
BACKGROUND OF THE INVENTION
Some internal combustion engine driven vehicles have been adapted
to drive a generator by an internal combustion engine to supply
power from the generator to various loads when the vehicles are
stopped. Especially in internal combustion engine driven vehicles
such as ATVs (All Terrain Vehicles), tractors, or recreation
vehicles that are internal combustion engine driven vehicles
intended mainly for driving on rough ground, a power supply unit
which uses a generator driven by an internal combustion engine for
driving a vehicle as a power supply to generate a commercial AC
output of AC 100 V or AC 200 V (50 Hz or 60 Hz) have been
incorporated, in order to allow electric tools or home appliances
to be used outdoors. Such a vehicle is disclosed in, for example,
U.S. Pat. No. 6,138,069 or Japanese Patent Application Laid-Open
Publication No. 2001-231106.
As a power transmission device that is provided between an internal
combustion engine and drive wheels, such a vehicle often uses a
transmission such as an automatic transmission or a continuously
variable transmission (CVT) having a gear position for cutting
power transmission, and an automatic clutch mechanism such as a
centrifugal clutch or a torque converter (fluid clutch) that enters
a state of transmitting power when a rotational speed of the engine
reaches a predetermined power transmission start rotational speed
or higher.
A power supply unit incorporated in such a vehicle has an
appropriate construction depending on a generator mounted to the
internal combustion engine. For example, when a magnetic AC
generator in which its field cannot be controlled is used as a
generator mounted to the internal combustion engine, a power supply
unit is comprised of a rectifier that rectifies the output of the
generator, an inverter that converts the output of the rectifier
into an AC output at commercial frequencies, and a filter that
eliminates harmonic components from the output of the inverter.
When a synchronous generator in which its field can be controlled
is used as the generator mounted to the internal combustion engine,
a power supply unit is comprised of the generator itself.
As described above, besides an internal combustion engine control
unit (ECU) that performs control required for operating the
internal combustion engine, a control device of an internal
combustion engine driven vehicle incorporating a power supply unit
includes: mode selection means for selecting a control mode of the
internal combustion engine between a control mode for driving
vehicle and a control mode for generating electric power; and a
generation control unit having rotational speed control means for
generating electric power for controlling an opening degree of a
throttle valve of the internal combustion engine or an ISC valve
(Idle Speed Control valve) that adjusts the amount of air flowing
through an air passage bypassing the throttle valve, so as to
rotate the internal combustion engine at a rotational speed
required for supplying predetermined power from the power supply
unit to a load when the control mode for generating electric power
is selected by the mode selection means.
The internal combustion engine control unit is comprised so as to
control an ignition timing and a fuel injection amount (when an
injector is used as fuel supply means) of the internal combustion
engine using various control conditions, such as a rotational speed
of the internal combustion engine, a throttle valve opening degree,
a temperature of the internal combustion engine, and a gear
position of a transmission provided between the internal combustion
engine and wheels.
The generation control unit has an appropriate construction
depending on the construction of the generator. For example, when
the magnetic AC generator is used as the generator, a main part of
the generation control unit is comprised of target rotational speed
arithmetic operation means for calculating a target rotational
speed of the internal combustion engine based on a deviation
between a target value of an output voltage of the inverter and an
output voltage of the rectifier, and rotational speed control means
for generating electric power for controlling an intake air amount
of the internal combustion engine so as to keep the rotational
speed of the internal combustion engine at the target rotational
speed.
Also, when the power supply unit described above is comprised of
the synchronous generator that can perform field control, a main
part of the generation control unit is comprised of rotational
speed control means for generating electric power for controlling
the intake air amount of the internal combustion engine so as to
rotate the internal combustion engine at a rotational speed
required for keeping output frequencies of the synchronous
generator at commercial frequencies, and field current control
means for controlling a field current of the generator so as to
keep an output voltage of the synchronous generator within a set
range.
In the case where the power transmission device including the
automatic clutch mechanism is used as described above, if a gear
position of the transmission is in a position other than a neutral
position or a parking position at the time of generation, and the
rotational speed is controlled by the rotational speed control
means for generating electric power in a state where power is
transmitted via the transmission, the automatic clutch enters a
state of transmitting power to cause runaway of the vehicle.
In order to prevent occurrence of such a situation, Japanese Patent
Application Laid-Open Publication No. 2001-231106 proposes that a
gear position sensor that detects a gear position of a transmission
is provided, and only when the sensor detects that the gear
position is in a position for cutting power transmission, a
rotational speed is controlled by rotational speed control means
for generating electric power.
However, even by such control, if a failure of the gear position
sensor or a failure of the power transmission device causes the
gear position sensor to detect by mistake that power transmission
is cut, in spite that the power transmission device is in a state
of transmitting power, the rotational speed is controlled by the
rotational speed control means for generating electric power, and
thus a possibility of runaway of the vehicle at the time of
generation cannot be completely eliminated.
In order to solve this problem, it is preferable to be able to
determine whether the power transmission device is in the state of
cutting power transmission or the state of transmitting power
(determine a power transmission state) independently of a gear
position sensor.
Thus, the applicant has previously proposed a method for
determining whether a power transmission device is in a state of
cutting power transmission or a state of transmitting power, from a
state of a load of an internal combustion engine independently of a
gear position sensor.
In the previously proposed method, an opening degree of a throttle
valve of the internal combustion engine is gradually increased to
gradually increase a rotational speed of the internal combustion
engine when a control mode for generating electric power is
selected by mode selection means. Then, in this process, when the
rotational speed reaches a power transmission start rotational
speed of an automatic clutch mechanism, the opening degree of the
throttle valve is further increased by a set opening degree that is
preset within a range so as not to start the vehicle, and when the
size of the load of the internal combustion engine is higher than a
reference value, it is determined that the power transmission
device is in the state of transmitting power.
Determination of the state of the power transmission device by such
a method prevents runaway of the vehicle when a failure of the gear
position sensor or a failure of the power transmission device
causes the gear position sensor to detect by mistake that power
transmission is cut, in spite that the power transmission device is
in the state of transmitting power.
However, if the power transmission state is determined from the
load of the internal combustion engine when the throttle valve
opening degree is gradually increased as the proposed method, it is
required to detect an amount that reflects a load in some way. When
the amount that reflects the load cannot be accurately detected, it
is required to estimate the size of the load by preparing a map for
estimating the load, but it is not easy to estimate the size of the
load accurately in a short time. If determination of the size of
the load takes long time, the transmission state of the power
transmission device cannot be determined before the vehicle starts,
and there is a possibility that runaway of the vehicle cannot be
prevented.
SUMMARY OF THE INVENTION
Therefore, an object of the invention is to provide a transmission
state determination method of a power transmission device for an
internal combustion engine driven vehicle, which can accurately
determine whether the power transmission device is in a state of
cutting power transmission or a state of transmitting power,
independently of a gear position sensor and without detecting a
load of the internal combustion engine, and a transmission state
determination device that implements the method.
Another object of the invention is to provide a runaway prevention
device of an internal combustion engine driven vehicle.
According to the invention, there is provided a method for
determining whether a power transmission device for an internal
combustion engine driven vehicle is in a state of cutting power
transmission or a state of transmitting power, the vehicle
including: an internal combustion engine incorporated in a vehicle
body having drive wheels; an AC generator incorporated in the
vehicle body and driven by the internal combustion engine; mode
selection means for selecting a control mode of the internal
combustion engine between a control mode for driving vehicle and a
control mode for generating electric power; and a generation
control unit having rotational speed control means for generating
electric power for controlling an intake air amount of the internal
combustion engine so as to rotate the internal combustion engine at
a rotational speed required for generating predetermined power from
the generator when the control mode for generating electric power
is selected by the mode selection means. The power transmission
device has a transmission with a gear position for cutting power
transmission and an automatic clutch mechanism and is provided
between a crankshaft of the internal combustion engine and the
drive wheels.
In the determination method according to the invention, a
displacement sensor that can detect movement of the vehicle body is
provided. The determination method comprises the steps of gradually
increasing the intake air amount of the internal combustion engine
while a rotational speed of the internal combustion engine is
monitored when the control mode for generating electric power is
selected; determining the power transmission device is in the state
of transmitting power when the displacement sensor detects movement
of the vehicle body in the process of gradually increasing the
intake air amount; and determining the power transmission device is
in the state of cutting power transmission when the displacement
sensor does not detect movement of the vehicle body before the
rotational speed of the internal combustion engine exceeds a preset
reference rotational speed in the process of gradually increasing
the intake air amount. The reference rotational speed is set to a
rotational speed when the automatic clutch mechanism starts power
transmission (power transmission start rotational speed) or
higher.
If the intake air amount of the internal combustion engine is
gradually increased from the amount of air at idling, the automatic
clutch mechanism enters the state of transmitting power when the
rotational speed of the internal combustion engine reaches the
power transmission start rotational speed. If the gear position of
the transmission of the power transmission device is in a position
for transmitting power at this time, part of a driving force of the
internal combustion engine is transmitted to the drive wheels to
cause the vehicle body to start. According to the invention, the
displacement sensor detects the movement of the vehicle body at
this time, and when the displacement sensor detects slight movement
of the vehicle body, it is determined that the power transmission
device is in the state of transmitting power.
Detecting the transmission state of the power transmission device
by this method ensures detection of the power transmission state of
the power transmission device, even when a failure of the gear
position sensor or a failure of the transmission of the power
transmission device prevents the gear position sensor from
accurately detecting the transmission state of the power
transmission device, for example, when a failure of the
transmission causes the transmission to be in the state of
transmitting power in spite that the gear position is in a neutral
position. Since detection of a load of the internal combustion
engine is not required, the invention can be readily applied to a
vehicle having no means for detecting a load of an internal
combustion engine.
Further, since the displacement sensor can instantaneously detect
whether the vehicle body moves, the transmission state of the power
transmission device can be rapidly determined, thus preventing
occurrence of a situation where delay in determination causes
impossibility of preventing runaway of the vehicle.
According to the invention, there is also provided a transmission
state determination device for determining whether a power
transmission device for an internal combustion engine driven
vehicle is in a state of cutting power transmission or a state of
transmitting power, the vehicle including: an internal combustion
engine incorporated in a vehicle body having drive wheels; an
actuator that operates means for adjusting an intake air amount of
the internal combustion engine; an AC generator incorporated in the
vehicle body and driven by the internal combustion engine; mode
selection means for selecting a control mode of the internal
combustion engine between a control mode for driving vehicle and a
control mode for generating electric power; and a generation
control unit having rotational speed control means for generating
electric power for controlling the intake air amount of the
internal combustion engine so as to rotate the internal combustion
engine at a rotational speed required for generating predetermined
power from the generator when the control mode for generating
electric power is selected by the mode selection means. The power
transmission device has a transmission with a gear position for
cutting power transmission and an automatic clutch mechanism and is
provided between a crankshaft of the internal combustion engine and
the drive wheels.
The transmission state determination device according to the
invention comprises rotational speed detection means for detecting
a rotational speed of the internal combustion engine and a
displacement sensor that detects movement of the vehicle body. The
transmission state determination device also comprises: intake air
amount control means for determining transmission state for
controlling the actuator so as to gradually increase the intake air
amount of the internal combustion engine when the control mode for
generating electric power is selected by the mode selection means;
and determination means for determining that the power transmission
device is in the state of transmitting power when the displacement
sensor detects movement of the vehicle body in the process of
gradually increasing the intake air amount by the intake air amount
control means for determining transmission state, and that the
power transmission device is in the state of cutting power
transmission when the displacement sensor does not detect movement
of the vehicle body before the rotational speed detected by the
rotational speed detection means exceeds a set reference rotational
speed in the process of gradually increasing the intake air
amount.
According to the invention, there is also provided a device for
preventing runaway of an internal combustion engine driven vehicle
when a control mode for generating electric power is selected, the
internal combustion engine driven vehicle including: an internal
combustion engine incorporated in a vehicle body having drive
wheels; a power transmission device that has a transmission with a
gear position for cutting power transmission and an automatic
clutch mechanism that enters a state of transmitting power when a
rotational speed of the internal combustion engine reaches a
predetermined power transmission start rotational speed or higher,
and is provided between a crankshaft of the internal combustion
engine and the drive wheels; an actuator that operates means for
adjusting an intake air amount of the internal combustion engine;
an AC generator incorporated in the vehicle body and driven by the
internal combustion engine; mode selection means for selecting a
control mode of the internal combustion engine between a control
mode for driving vehicle and a control mode for generating electric
power; and a generation control unit having rotational speed
control means for generating electric power for controlling the
intake air amount of the internal combustion engine so as to rotate
the internal combustion engine at a rotational speed required for
generating predetermined power from the generator when the control
mode for generating electric power is selected by the mode
selection means.
The runaway prevention device according to the invention includes:
rotational speed detection means for detecting a rotational speed
of the internal combustion engine; a displacement sensor that
detects movement of the vehicle body; intake air amount control
means for determining transmission state for controlling the
actuator so as to gradually increase the intake air amount of the
internal combustion engine when the control mode for generating
electric power is selected by the mode selection means;
determination means for determining that the power transmission
device is in a state of transmitting power when the displacement
sensor detects movement of the vehicle body in the process of
gradually increasing the intake air amount by the intake air amount
control means for determining transmission state, and that the
power transmission device is in a state of cutting power
transmission when the displacement sensor does not detect movement
of the vehicle body before the rotational speed detected by the
rotational speed detection means exceeds a reference rotational
speed in the process of gradually increasing the intake air amount;
and safety means for controlling the internal combustion engine so
as to return the rotational speed of the internal combustion engine
to a rotational speed less than the power transmission start
rotational speed or to stop the internal combustion engine when the
determination means determines that the power transmission device
is in the state of transmitting power.
BRIEF DESCRIPTION OF THE DRAWINGS
The above and other objects and features of the present invention
will be apparent from the detailed description of the preferred
embodiment of the invention, which is described and illustrated
with reference to the accompanying drawings, in which;
FIG. 1 is a schematic diagram of a construction of a vehicle to
which the invention is applied;
FIG. 2 is a block diagram of an entire construction of an
embodiment of the invention; and
FIG. 3 is a flowchart of an example of an algorithm of essential
portions of a program executed by a microprocessor in order to
implement a method of the invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Now, an embodiment of the invention will be described with
reference to the drawings.
The invention is applied to an internal combustion engine driven
vehicle such as an ATV (All Terrain Vehicle), a tractor, or a
recreational vehicle. However, an internal combustion engine driven
vehicle to which the invention is applied may incorporate a power
supply unit that uses an AC generator mounted to an internal
combustion engine for driving the vehicle as a power supply to
generate AC power at predetermined frequencies, and use, a
structure, and a type of the vehicle are arbitrary.
FIG. 1 shows an example of an entire construction of an internal
combustion engine driven vehicle to which the invention is applied,
and FIG. 2 is a block diagram of an entire construction of an
embodiment of the invention.
In FIG. 1, a reference numeral 1 denotes an internal combustion
engine incorporated in a vehicle body (not shown). An end of a
crankshaft 1a of the internal combustion engine 1 is connected to
an axle 9 supported by the vehicle body, via a power transmission
device 6 including an automatic clutch 2 and a CVT (continuously
variable transmission) 5 having a belt transmission mechanism 3 and
a gear box 4, and a gear mechanism 7. Drive wheels 8 of the vehicle
are mounted to the axle 9.
The automatic clutch mechanism 2 according to the embodiment is a
centrifugal clutch mechanism, and enters a state of transmitting
power when a rotational speed of the internal combustion engine
reaches a power transmission start rotational speed.
A gear position selection lever 4a is mounted to the gear box 4,
and the lever is operated to switch a gear position to a parking
position P, a high position H, a low position L, a neutral position
N, or a reverse (backing up) position R. A gear position sensor 10
that detects the gear position is mounted to the gear box 4. Among
the gear positions, the neutral position N and the parking position
P are positions for cutting power transmission from the internal
combustion engine to the drive wheels, and the high position H, the
low position L, and the reverse (backing up) position R are
positions for transmitting power from the internal combustion
engine to the drive wheels.
A throttle valve 12 is mounted to an intake pipe 1b of the internal
combustion engine, and an output shaft of an electric actuator 13
is connected to an operation shaft of the throttle valve. An input
shaft of a throttle sensor 14 that generates an electric signal
proportional to an opening degree of the throttle valve is also
connected to the operation shaft of the throttle valve 12.
An unshown injector (an electromagnetic fuel injection valve) is
mounted to the intake pipe 1b of the internal combustion engine 1,
and an ignition plug is mounted to a cylinder head of the internal
combustion engine.
A rotor of a generator 15 is mounted to the other end of the
crankshaft 1a of the internal combustion engine 1. A stator of the
generator is secured to a mounting portion provided on a case or a
cover of the internal combustion engine.
The shown generator 15 is a magnetic AC generator, and an AC output
obtained from the generator 15 is input to an inverter/controller
unit 16.
The inverter/controller unit 16 includes, in one unit, a rectifier
16A that rectifies the AC output of the generator 15, an inverter
16B that converts the output of the rectifier 16A into an AC
output, and a controller 16C, as shown in FIG. 2. The controller
16C includes inverter control means for controlling the inverter
16B so as to output an AC voltage V.sub.0 at commercial frequencies
from the inverter 16B, and target rotational speed arithmetic
operation means for arithmetically operating, as a target
rotational speed N.sub.0, a rotational speed of the internal
combustion engine required for matching the output voltage of the
inverter with a target value based on a deviation between a target
value of the AC voltage (an effective value) output from the
inverter and a DC voltage output from the rectifier.
In this embodiment, a power supply unit that generates an AC
voltage at commercial frequencies when the vehicle is stopped is
comprised of the generator 15 and the inverter/controller unit
16.
In FIG. 1, a reference numeral 17 denotes a control device having a
microprocessor, and mode selection means 18 constituted by a
manually operated mode selection switch (MSW) provides a selection
instruction to the control device to select a control mode between
a control mode for driving vehicle and a control mode for
generating electric power. The selection instruction issued by the
mode selection means 18 is also provided to the controller in the
inverter/controller unit 16.
A signal generator 19 that generates a pulse signal at a particular
crank angle position of the internal combustion engine is mounted
to the internal combustion engine 1, and the output of the signal
generator is input to the control device 17 together with the
output of the gear position sensor 10 and the output of the
throttle sensor 14.
The shown signal generator 19 is comprised so as to generate a
pulse signal when a leading edge and a trailing edge in a
rotational direction of a reluctor (inductor) 19a constituted by a
protrusion on an outer periphery of a rotor yoke of the generator
15 are detected.
A reference numeral 20 denotes a vehicle speed sensor comprised so
as to output a vehicle speed pulse for each rotation of the axle 9
through a certain angle, and in this embodiment, the vehicle speed
sensor is used as a displacement sensor that detects movement of
the vehicle body. The output of the vehicle speed sensor 20 is
input to the control device 17. The vehicle speed sensor 20 is
known and comprised of a rotor mounted to the axle 9 or provided so
as to rotate synchronously with the axle 9, and a sensor (a pickup
coil or a Hall IC) that detects a reluctor or a magnet provided on
the rotor to generate a pulse for each rotation of the axle through
a certain angle.
The inverter control means provided in the controller 16C of the
inverter/controller unit 16 controls on/off of a switch element
that constitutes the inverter at a predetermined timing so as to
output the AC voltage at predetermined frequencies (generally,
commercial frequencies) from the inverter.
The target rotational speed arithmetic operation means provided in
the controller 16C arithmetically operates, as the target
rotational speed, the rotational speed of the internal combustion
engine required for matching the output voltage of the inverter
with the target value based on the deviation between the target
value of the AC voltage V.sub.0 output from the inverter 16B and
the DC voltage output from the rectifier 16A that rectifies the
output of the generator 15, and provides a signal that indicates
the target rotational speed to the control device 17.
Various sensors (not shown) that detect control conditions
(temperature of the internal combustion engine, atmospheric
pressure, or the like) used for controlling an ignition timing and
a fuel injection amount of the internal combustion engine are
provided, and outputs of the sensors are input to the control
device 17.
The control device 17 is comprised of an internal combustion engine
control unit (ECU) that performs control required for operating the
internal combustion engine (control of an ignition timing or
control of fuel injection time); a generation control unit that
controls a throttle valve opening degree of the internal combustion
engine to control an intake air amount of the internal combustion
engine so as to rotate the internal combustion engine at a
rotational speed required for supplying predetermined power from
the power supply unit to a load, and a determination/safety control
unit that determines whether the power transmission device is in a
state of transmitting power when the control mode is shifted to the
control mode for generating electric power, and performs control
for preventing increase in the rotational speed of the internal
combustion engine when it is determined that the power transmission
device is in the state of transmitting power.
As shown in FIG. 2, the internal combustion engine control unit
includes: an ignition device 23 that provides a high voltage for
ignition to an ignition plug to perform an ignition operation when
an ignition signal is provided; a fuel injection device 24 that
provides a drive current to the injector to inject fuel from the
injector when an injection instruction signal is provided;
rotational speed detection means 25 for arithmetically operating
the rotational speed of the internal combustion engine from a
generation interval (a time required for the crankshaft to rotate
through a certain angle) of pulse signals output by the signal
generator 19; an ignition/injection control unit 26 that controls
the ignition device 23 and the fuel injection device 24 in
accordance with the arithmetically operated rotational speed and
the various control conditions such as the throttle valve opening
degree; and throttle control means for driving vehicle 27 for
controlling the actuator 13 so as to adjust the opening degree of
the throttle valve 12 in accordance with a driver's accelerator
operation when the control mode for driving vehicle is selected by
the mode selection means 18.
The ignition/injection control means 26 is comprised of ignition
timing arithmetic operation means and injection amount arithmetic
operation means for arithmetically operating an ignition timing and
a fuel injection amount, respectively, of the internal combustion
engine; ignition signal generation means for generating an ignition
signal to be provided to an ignition circuit when the
arithmetically operated ignition timing is detected; and injection
instruction signal generation means for generating an injection
instruction signal to be provided to an injector drive circuit when
a predetermined injection start timing is detected.
The injection instruction signal is a rectangular wave signal
having a signal width required for injecting the fuel of the
arithmetically operated injection amount, and the fuel is injected
from the injector while the injection instruction signal is
generated.
The generation control unit performs control required for keeping
the AC output voltage output from the inverter of the
inverter/controller unit 16 within a set range, and includes
rotational speed control means for generating electric power 28 for
controlling the actuator 13 to adjust the opening degree of the
throttle valve 12 so as to match the rotational speed of the
internal combustion engine 1 with the target rotational speed
arithmetically operated by the controller in the
inverter/controller unit 16, when the control mode for generating
electric power is selected by the mode selection means 18, and the
gear position sensor 10 detects that the gear position of the
transmission 5 is in the neutral position or the parking
position.
The generation control unit is comprised so that the rotational
speed control means for generating electric power performs control
only when the control mode for generating electric power is
selected by the mode selection means 18 in a state where the gear
position sensor 10 detects that the gear position is in the neutral
position N or the parking position P (both are the gear positions
for cutting power transmission), and a shift to the control mode
for generating electric power is not performed when the control
mode for generating electric power is selected by the mode
selection means 18 in a state where the gear position switch is not
in the neutral position or the parking position.
The determination/safety control unit determines a transmission
state of the power transmission device by the method according to
the invention when the control mode for generating electric power
is selected, and controls to reduce the rotational speed of the
internal combustion engine to a rotational speed less than the
power transmission start rotational speed or to stop the internal
combustion engine in order to prevent runaway of the vehicle when
it is determined that the power transmission device is in the state
of transmitting power.
The determination/safety control unit according to the embodiment
is comprised of intake air amount control means for determining
transmission state 30 for controlling the actuator 13 so as to
gradually increase the throttle valve opening degree of the
internal combustion engine (gradually increase the intake air
amount) when the control mode for generating electric power is
selected by the mode selection means; determination means 31 for
determining that the power transmission device is in the state of
transmitting power when slight movement of the vehicle body is
detected from the vehicle speed pulse output by the vehicle speed
sensor 20 (displacement sensor) in the process of gradually
increasing the throttle valve opening degree to increase the intake
air amount by the control means 30, and that the power transmission
device is in the state of cutting power transmission when movement
of the vehicle body is not detected from the vehicle speed pulse
before the rotational speed detected by the rotational speed
detection means exceeds a reference rotational speed set to the
power transmission start rotational speed of the automatic clutch
mechanism 2 or higher in the process of gradually increasing the
intake air amount; and safety means 33 for controlling the engine
so as to return the rotational speed of the internal combustion
engine to a rotational speed less than the power transmission start
rotational speed or to stop the internal combustion engine when the
determination means determines that the power transmission device
is in the state of transmitting power.
The safety means 33 may be comprised of means for controlling the
actuator 13 so as to return the throttle valve opening degree to an
idle opening degree when the determination means 31 determines that
the power transmission device is in the state of transmitting
power, or means for stopping an ignition operation of the internal
combustion engine when the determination means 31 determines that
the power transmission device is in the state of transmitting
power. The safety means 33 may be also comprised of means for
stopping supply of fuel to the internal combustion engine when the
determination means 31 determines that the power transmission
device is in the state of transmitting power.
In the example in FIG. 2, it is assumed that the safety means 33 is
comprised of the means for stopping the ignition operation of the
internal combustion engine 1 when the determination means 31
determines that the power transmission device is in the state of
transmitting power, or the means for stopping supply of fuel to the
internal combustion engine (stopping fuel injection from the
injector) when the determination means 31 determines that the power
transmission device is in the state of transmitting power.
In the internal combustion engine driven vehicle in FIG. 1, when
the control mode for driving vehicle is selected by the mode
selection means 18, the throttle control means for driving vehicle
27 controls the actuator 13 so as to adjust the opening degree of
the throttle valve 12 in accordance with the driver's accelerator
operation, and controls the rotational speed of the internal
combustion engine 1 so as to cause the vehicle to drive at a
predetermined rotational speed.
In driving the vehicle, it is not always necessary that the
throttle control means for driving vehicle 27 controls the actuator
so as to adjust the throttle valve opening degree, but the throttle
control means for driving vehicle 27 may be omitted to mechanically
operate the throttle valve in accordance with the driver's
accelerator operation.
When the control mode for generating electric power is selected by
the mode selection means 18 in the state where the gear position
sensor 10 detects that the gear position is in the neutral position
N or the parking position P, the control device 17 first performs a
determination process for determining whether the power
transmission device 6 is in the state of cutting power transfer or
the state of transmitting power by the transmission state
determination method according to the invention, and when it is
determined that the power transmission device 6 is in the state of
cutting power transmission, the control mode is shifted to the
control mode for generating electric power to cause the rotational
speed control means for generating electric power to perform
control. When it is determined in the determination process that
the power transmission device is in the state of transmitting
power, the safety means 33 controls the engine so as to return the
rotational speed of the internal combustion engine to the
rotational speed less than the power transmission start rotational
speed or to stop the internal combustion engine.
In the determination process for determining the transmission state
of the power transmission device, the transmission state
determination means according to the invention determines whether
the power transmission device is in the state of transmitting
power. Specifically, in the determination process, the intake air
amount control means for determining transmission state 30 drives
the actuator 13 while monitoring the rotational speed of the
internal combustion engine 1 to gradually increase the opening
degree of the throttle valve 12 of the internal combustion engine
to increase the intake air amount of the engine. Then, it is
determined that the power transmission device 6 is in the state of
transmitting power when slight movement of the vehicle body is
detected from the output of the vehicle speed sensor 20 before the
rotational speed of the internal combustion engine exceeds the
reference rotational speed set to the power transmission start
rotational speed (the rotational speed when the automatic clutch
mechanism 2 starts power transmission) or higher in the process of
gradually increasing the intake air amount, and that the power
transmission device 6 is in the state of cutting power transmission
when movement of the vehicle body is not detected from the output
of the vehicle speed sensor 20 before the rotational speed of the
internal combustion engine exceeds the reference rotational speed
set to the power transmission start rotational speed or higher in
the process of gradually increasing the intake air amount.
For detecting from the output of the vehicle speed sensor whether
the vehicle body slightly moves, a vehicle speed may be
arithmetically operated from the generation interval (time) of the
vehicle speed pulses output by the vehicle speed sensor and the
diameter of the wheel to detect that the vehicle body moves when
the arithmetically operated vehicle speed reaches a determination
reference value preset to a sufficiently low value (for example, 2
km/h) or higher, and that the vehicle body does not move when the
vehicle speed does not reach the determination reference value.
Alternatively, it may be determined that the power transmission
device is in the state of transmitting power when at least one
vehicle speed pulse is detected in the process of gradually
increasing the intake air amount, and that the power transmission
device is in the state of cutting power transmission when no
vehicle speed pulse is detected before the rotational speed of the
internal combustion engine exceeds the reference rotational speed
set to the power transmission start rotational speed or higher in
the process of gradually increasing the intake air amount.
Thus, it is determined that the power transmission device is in the
state of transmitting power when at least one vehicle speed pulse
is detected in the process of gradually increasing the intake air
amount, thereby allowing rapid detection that the power
transmission device is in the state of transmitting power. This
ensures preventing the vehicle from moving when the power
transmission device is in the state of transmitting power for some
reason, in the state where the gear position sensor 10 detects that
the gear position is in the neutral position N or the parking
position P when the control mode is shifted to the control mode for
generating electric power.
In the embodiment, the transmission state determination device of
the power transmission device for the internal combustion engine
driven vehicle is comprised of the rotational speed detection means
25 provided in the control device 17, the intake air amount control
means for determining transmission state 30, and the determination
means 31.
The runaway prevention device of the internal combustion engine
driven vehicle is comprised of the transmission state determination
device and the safety means 33.
The control device 17 in the example in FIG. 1 includes the
microprocessor, and a predetermined program is executed by the
microprocessor to construct various means required for constructing
the internal combustion engine control unit, the generation control
unit, and the determination/safety control unit. FIG. 3 shows an
example of an algorithm of essential portions of the program
executed by the microprocessor in order to construct the
determination/safety control unit.
According to the algorithm, first in Step 1, it is determined
whether the control mode selection switch MSW that constitutes the
mode selection means is in an on state (whether the control mode
for generating electric power is selected). When it is determined
that the control mode selection switch is in the on state and the
control mode for generating electric power is selected, the process
goes to Step 2, and it is determined whether the gear position of
the transmission is in the neutral position N or the parking
position P. When the gear position GP of the transmission is not in
the neutral position N or the parking position P (the position for
cutting power transmission), the process goes to Step 3, and an
alarm is raised to prohibit a shift to the control mode for
generating electric power.
In Step 2, when it is determined that the gear position of the
transmission is in the neutral position N or the parking position
P, the process goes to Step 4, and the actuator 13 is controlled so
as to gradually increase the throttle valve opening degree
.theta.th from the idle opening degree to gradually increase the
rotational speed Vn of the internal combustion engine. Then, it is
determined in Step 5 whether the vehicle speed pulse is detected,
and when the vehicle speed pulse is detected, the process goes to
Step 6 to determine that the power transmission device is in the
state of transmitting power (an on state). Then, an alarm is raised
in Step 7, and the internal combustion engine is stopped in Step
8.
When the vehicle speed pulse is not detected in Step 5, the process
goes to Step 9, and it is determined whether the rotational speed
Vn exceeds the reference rotational speed Vns set to the power
transmission start rotational speed or higher, and when the
rotational speed does not exceed the reference rotational speed,
the process returns to Step 2. When it is determined in Step 9 that
the rotational speed of the engine exceeds the reference rotational
speed, the process goes to Step 10 to determine that the power
transmission device is in the state of cutting power transmission
(an off state), and the control mode is shifted to the control mode
for generating electric power in Step 11.
When it is determined in Step 1 that the control mode selection
switch MSW is in an off state, the process goes to Step 12, and the
control mode is shifted to the vehicle control mode for driving
vehicle.
According to the algorithm in FIG. 3, in Step 4, the intake air
amount control means for determining transmission state 30 is
comprised, and in Steps 5, 6, 9, and 10, the determination means 31
is comprised. In Step 7, the safety means 33 is comprised.
In the example, the vehicle speed sensor 20 is mounted to the axle
9 to which the drive wheels 8 are mounted, but the vehicle speed
sensor 20 may be mounted to an axle on the non-drive side.
In the embodiment, the magneto generator is used as the generator,
but a synchronous generator in which its field can be controlled
may be used. When the synchronous generator in which its field can
be controlled is used, the rotational speed of the internal
combustion engine is controlled and kept constant, and a field
current is controlled so as to keep an output voltage of the
generator at a set value so that output frequencies of the
generator reach predetermined frequencies when the control mode is
shifted to the control mode for generating electric power.
In the embodiment, the actuator is mounted to the throttle valve,
and the intake air amount of the engine is changed by changing the
opening degree of the throttle valve when the control mode for
generating electric power is selected. However, when an ISC valve
(Idle Speed Control valve) or an IAC valve (Idle Air Control valve)
that adjusts the amount of air flowing through an air passage
bypassing the throttle valve is provided, the intake air amount of
the engine may be changed by controlling the opening degree of the
valve.
In the embodiment, the centrifugal clutch mechanism is used as the
automatic clutch mechanism, but the invention may be applied to the
case where a torque converter (fluid clutch) is used as an
automatic clutch mechanism.
In the embodiment, the continuously variable transmission is used
as the transmission provided in the power transmission device, but
the invention may be applied to the case where an automatic
transmission that stepwise changes the transmission gear ratio is
used.
The preferable embodiment has been described above, and the
invention disclosed herein will be organized as described
below.
The transmission state determination method according to the
invention is the method for determining whether the power
transmission device for the internal combustion engine driven
vehicle is in the state of cutting power transmission or the state
of transmitting power, the power transmission device including: the
internal combustion engine incorporated in the vehicle body having
the drive wheels; the power transmission device that has the
transmission with the gear position for cutting power transmission
and the automatic clutch mechanism and is provided between the
crankshaft of the internal combustion engine and the drive wheels;
the AC generator incorporated in the vehicle body and driven by the
internal combustion engine; the mode selection means for selecting
the control mode of the internal combustion engine between the
control mode for driving vehicle and the control mode for
generating electric power; and the generation control unit having
the rotational speed control means for generating electric power
for controlling the intake air amount of the internal combustion
engine so as to rotate the internal combustion engine at the
rotational speed required for generating the predetermined power
from the generator when the control mode for generating electric
power is selected by the mode selection means.
In the invention, the displacement sensor that can detect movement
of the vehicle body is prepared, and the intake air amount of the
internal combustion engine is gradually increased while the
rotational speed of the internal combustion engine is monitored
when the control mode for generating electric power is selected.
When the displacement sensor detects movement of the vehicle body
in this process, it is determined that the power transmission
device is in the state of transmitting power. When the displacement
sensor does not detect movement of the vehicle body before the
rotational speed of the internal combustion engine exceeds the
preset reference rotational speed in the process of gradually
increasing the intake air amount, it is determined that the power
transmission device is in the state of cutting power
transmission.
The reference rotational speed is set to the rotational speed when
the automatic clutch mechanism starts power transmission (power
transmission start rotational speed) or higher.
The displacement sensor may be a sensor that can detect movement of
the vehicle body by the power transmitted from the internal
combustion engine through the power transmission device. As the
displacement sensor, a sensor that detects displacement (rotation)
of the axle or displacement of the wheels, or a sensor that detects
slight displacement of the vehicle body itself may be used. A
general vehicle has a vehicle speed sensor that generates a vehicle
speed pulse for each rotation of an axle through a certain angle,
and it is convenient to use the vehicle speed sensor as the
displacement sensor.
As the sensor that detects displacement of the vehicle body itself,
for example, an acceleration sensor can be used.
In a preferable mode of the invention, the vehicle speed sensor
that generates a vehicle speed pulse for each rotation of the axle
of the vehicle through a certain angle is used as the displacement
sensor. When the vehicle speed sensor is used as the displacement
sensor, the intake air amount of the internal combustion engine is
gradually increased while the rotational speed of the internal
combustion engine is monitored when the control mode for generating
electric power is selected, and when generation of the vehicle
speed pulse by the vehicle speed sensor is detected in the process
of gradually increasing the intake air amount, it is determined
that the power transmission device is in the state of transmitting
power. When generation of the vehicle speed pulse by the vehicle
speed sensor is not detected before the rotational speed of the
internal combustion engine exceeds the preset reference rotational
speed in the process of gradually increasing the intake air amount,
it is determined that the power transmission device is in the state
of cutting power transmission.
In the case where the vehicle speed sensor is used as the
displacement sensor, it may be determined that the power
transmission device is in the state of transmitting power when the
vehicle speed obtained from the vehicle speed pulse reaches the set
determination reference value or higher in the process of gradually
increasing the intake air amount, and that the power transmission
device is in the state of cutting power transmission when the
vehicle speed obtained from the vehicle speed pulse does not reach
the determination reference value before the rotational speed of
the internal combustion engine exceeds the preset reference
rotational speed in the process of gradually increasing the intake
air amount.
The transmission state determination device according to the
invention is the device for determining whether the power
transmission device for the internal combustion engine driven
vehicle is in the state of cutting power transmission or the state
of transmitting power, the power transmission device including: the
internal combustion engine incorporated in the vehicle body having
the drive wheels; the power transmission device that has the
transmission with the gear position for cutting power transmission
and the automatic clutch mechanism and is provided between the
crankshaft of the internal combustion engine and the drive wheels;
the actuator that operates the means for adjusting the intake air
amount of the internal combustion engine; the AC generator
incorporated in the vehicle body and driven by the internal
combustion engine; the mode selection means for selecting the
control mode of the internal combustion engine between the control
mode for driving vehicle and the control mode for generating
electric power; and the generation control unit having the
rotational speed control means for generating electric power for
controlling the intake air amount of the internal combustion engine
so as to rotate the internal combustion engine at the rotational
speed required for generating the predetermined power from the
generator when the control mode for generating electric power is
selected by the mode selection means.
The transmission state determination device according to the
invention includes: the rotational speed detection means for
detecting the rotational speed of the internal combustion engine;
the displacement sensor that detects movement of the vehicle body;
the intake air amount control means for determining transmission
state for controlling the actuator so as to gradually increase the
intake air amount of the internal combustion engine when the
control mode for generating electric power is selected by the mode
selection means; and the determination means for determining that
the power transmission device is in the state of transmitting power
when the displacement sensor detects movement of the vehicle body
in the process of gradually increasing the intake air amount by the
intake air amount control means for determining transmission state,
and that the power transmission device is in the state of cutting
power transmission when the displacement sensor does not detect
movement of the vehicle body before the rotational speed detected
by the rotational speed detection means exceeds the set reference
rotational speed in the process of gradually increasing the intake
air amount.
In a preferable mode of the invention, the vehicle speed sensor
that generates a vehicle speed pulse for each rotation of the axle
of the vehicle through a certain angle is used as the displacement
sensor.
In this case, the determination means is comprised so as to
determine that the power transmission device is in the state of
transmitting power when the vehicle speed pulse is detected in the
process of gradually increasing the intake air amount by the intake
air amount control means for determining transmission state, and
that the power transmission device is in the state of cutting power
transmission when the vehicle speed pulse is not detected before
the rotational speed detected by the rotational speed detection
means exceeds the reference rotational speed in the process of
gradually increasing the intake air amount.
In the case where the vehicle speed sensor that generates a vehicle
speed pulse for each rotation of the axle of the vehicle through a
certain angle is used as the displacement sensor, the determination
means may be comprised so as to determine that the power
transmission device is in the state of transmitting power when the
vehicle speed obtained from the vehicle speed pulse reaches the set
determination reference value or higher in the process of gradually
increasing the intake air amount by the intake air amount control
means for determining transmission state, and that the power
transmission device is in the state of cutting power transmission
when the vehicle speed obtained from the vehicle speed pulse does
not reach the determination reference value before the rotational
speed of the internal combustion engine exceeds the predetermined
reference rotational speed in the process of gradually increasing
the intake air amount.
The runaway prevention device according to the invention is the
device for preventing runaway of the internal combustion engine
driven vehicle when the control mode for generating electric power
is selected, the internal combustion engine driven vehicle
including: the internal combustion engine incorporated in the
vehicle body having the drive wheels; the power transmission device
that has the transmission with the gear position for cutting power
transmission and the automatic clutch mechanism that enters the
state of transmitting power when the rotational speed of the
internal combustion engine reaches the predetermined power
transmission start rotational speed or higher, and is provided
between the crankshaft of the internal combustion engine and the
drive wheels; the actuator that operates the means for adjusting
the intake air amount of the internal combustion engine; the AC
generator incorporated in the vehicle body and driven by the
internal combustion engine; the mode selection means for selecting
the control mode of the internal combustion engine between the
control mode for driving vehicle and the control mode for
generating electric power; and the generation control unit having
the rotational speed control means for generating electric power
for controlling the intake air amount of the internal combustion
engine so as to rotate the internal combustion engine at the
rotational speed required for generating the predetermined power
from the generator when the control mode for generating electric
power is selected by the mode selection means.
The runaway prevention device according to the invention includes:
the rotational speed detection means for detecting the rotational
speed of the internal combustion engine; the displacement sensor
that detects movement of the vehicle body; the intake air amount
control means for determining transmission state for controlling
the actuator so as to gradually increase the intake air amount of
the internal combustion engine when the control mode for generating
electric power is selected by the mode selection means; the
determination means for determining that the power transmission
device is in the state of transmitting power when the displacement
sensor detects movement of the vehicle body in the process of
gradually increasing the intake air amount by the intake air amount
control means for determining transmission state, and that the
power transmission device is in the state of cutting power
transmission when the displacement sensor does not detect movement
of the vehicle body before the rotational speed detected by the
rotational speed detection means exceeds the set reference
rotational speed in the process of gradually increasing the intake
air amount; and the safety means for controlling the internal
combustion engine so as to return the rotational speed of the
internal combustion engine to the rotational speed less than the
power transmission start rotational speed or to stop the internal
combustion engine when the determination means determines that the
power transmission device is in the state of transmitting
power.
When the vehicle speed sensor that generates a plurality of vehicle
speed pulses for one rotation of the axle of the vehicle is used as
the displacement sensor, the determination means is comprised so as
to determine that the power transmission device is in the state of
transmitting power when the vehicle speed pulses are detected in
the process of gradually increasing the intake air amount by the
intake air amount control means for determining transmission state,
and that the power transmission device is in the state of cutting
power transmission when the vehicle speed pulses are not detected
before the rotational speed detected by the rotational speed
detection means exceeds the set reference rotational speed in the
process of gradually increasing the intake air amount, or comprised
so as to determine that the power transmission device is in the
state of transmitting power when the vehicle speed obtained from
the vehicle speed pulses reaches the set determination reference
value or higher in the process of gradually increasing the intake
air amount by the intake air amount control means for determining
transmission state, and that the power transmission device is in
the state of cutting power transmission when the vehicle speed
obtained from the vehicle speed pulses does not reach the
determination reference value before the rotational speed of the
internal combustion engine exceeds the predetermined reference
rotational speed.
The safety means may be comprised of the means for controlling the
actuator so as to return the intake air amount to an idle air
amount when the determination means determines that the power
transmission device is in the state of transmitting power.
The safety means may be comprised of the means for stopping the
ignition operation of the internal combustion engine when the
determination means determines that the power transmission device
is in the state of transmitting power.
The safety means may be comprised of the means for stopping supply
of fuel to the internal combustion engine when the determination
means determines that the power transmission device is in the state
of transmitting power.
Although a preferred embodiment of the invention has been described
and illustrated with reference to the accompanying drawings, it
will be understood by those skilled in the art that they are by way
of examples, and that various changes and modifications may be made
without departing from the spirit and scope of the invention, which
is defined only to the appended claims.
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